Re: [PATCH 1/5] target/arm: only build psci for TCG

[Fabiano Rosas]

Claudio Fontana <cfontana@suse.de> writes:

> Ciao Alex,
>
> On 12/19/22 11:47, Alexander Graf wrote:
>> Hey Claudio,
>> 
>> On 19.12.22 09:37, Claudio Fontana wrote:
>>>
>>> On 12/16/22 22:59, Alexander Graf wrote:
>>>> Hi Claudio,
>>>>
>>>> If the PSCI implementation becomes TCG only, can we also move to a tcg 
>>>> accel directory? It slowly gets super confusing to keep track of which 
>>>> files are supposed to be generic target code and which ones TCG specific>
>>>> Alex
>>> Hi Alex, Fabiano, Peter and all,
>>>
>>> that was the plan but at the time of:
>>>
>>> https://lore.kernel.org/all/20210416162824.25131-1-cfontana@suse.de/
>>>
>>> Peter mentioned that HVF AArch64 might use that code too:
>>>
>>> https://lists.gnu.org/archive/html/qemu-devel/2021-03/msg00509.html
>>>
>>> so from v2 to v3 the series changed to not move the code under tcg/ , 
>>> expecting HVF to be reusing that code "soon".
>>>
>>> I see that your hvf code in hvf/ implements psci, is there some plan to 
>>> reuse pieces from the tcg implementation now?
>> 
>> I originally reused the PSCI code in earlier versions of my hvf patch 
>> set, but then we realized that some functions like remote CPU reset are 
>> wired in a TCG specific view of the world with full target CPU register 
>> ownership. So if we want to actually share it, we'll need to abstract it 
>> up a level.
>> 
>> Hence I'd suggest to move it to a TCG directory for now and then later 
>> move it back into a generic helper if we want / need to. The code just 
>> simply isn't generic yet.
>> 
>> Or alternatively, you create a patch (set) to actually merge the 2 
>> implementations into a generic one again which then can live at a 
>> generic place :)
>> 
>> 
>> Alex
>
> Thanks for the clarification, I'll leave the choice up to Fabiano now, since 
> he is working on the series currently :-)
>
> Ciao,
>
> Claudio

Hello, thank you all for the comments.

I like the idea of merging the two implementations. However, I won't get
to it anytime soon. There's still ~70 patches in the original series
that I need to understand, rebase and test, including the introduction
of the tcg directory.

I'd say we merge this as is now, since this patch has no
dependencies. Later when I introduce the tcg directory I can move the
code there along with the other tcg-only files. I'll take note to come
back to the PSCI code as well.